help with too many cpu options

Its time to upgrade and I've been out of the loop. I've been reading over toms hardware and was also hoping to cheat by asking on here.

I wont be able to keep my PC2700 ram with anything new will I?

Here's the CPU's I'm looking at, what do you think and could you tell me what socket they are? Oh and I havent bought ram since the 2700, what do you go buy now? This will be for video games and your normal internet crap.

athlon 64 x2 3800 am2
athlon 64 x2 4200 am2
core 2 duo e6300 1.86ghz
pentium d 930
pentium d 940

these are pretty much the best CPU's I could find in the $175ish range, some are closer to 150

I have not considered P4 as an option, should I?